Technology update

Galvanic displacement lays down nanoparticle films

Scientists from Purdue University, US, have used galvanic displacement from aqueous metal salt solutions to lay down nanoparticle films of gold, palladium and platinum onto semiconductor chips. The researchers patterned these films by photolithography, microcontact printing and dip-pen nanolithography.

"All you need to do to form nanoparticles is dip the semiconductor into the solution and wait," said Purdue researcher Lon Porter. "Though you begin with a solution worth less than the change in your pocket, you still end up with a layer of gold nanoparticles that has the same purity as gold bullion."

The scientists deposited the films onto germanium, copper, zinc and tin substrates, from dilute aqueous solutions of chloride salts. The technique's applications include interfacing nanoparticles with metals and semiconductors, and high-surface-area catalysts.

"We are not sure what application of our discoveries will appear first," said Jillian Buriak. "But there are many semiconductor companies out there that spend a lot of money on chip interfacing, and we expect they could all take advantage of this technique somehow."